The present invention relates to a dental instrument for removing caries attacked dentine.
In traditional caries treatment the attacked tooth substance is removed mechanically by means of a dentist""s drill or a cutting excavator. Such a caries treatment is often a painful and unpleasant experience for the patient. Some of the patients feel so uncomfortable with the treatment that they wait far too long before they visit a dentist, which means that it is often too late to save the caries attacked teeth. Extraction of the teeth is then the only treatment method that is left.
However, there are other methods which are based on a chemical-mechanical treatment for the removal of the caries attacked substance. Such methods are described in SE 460258, SE 507437 and SE 98.00025-0. According to these methods a preparation in the form of a two-component liquid is mixed and then immediately applied to the caries lesion. Functioning in a biological way, the liquid makes the caries attacked substance soft without causing any damage to the tooth or the soft tissue. After 10-15 seconds the dentist can start removing the carious substance by means of a scraping instrument. The scraping continues until all caries substance has been removed. Then the cavity is filled with a suitable filling material.
According to SE 460258 the two-component liquid consists of a sodium hypochlorite component and a nitrogen-containing. component. The nitrogen-containing component consists in this case of three nitrogen-containing compounds with different charge states in its side chain; one neutral, one with a negative net charge and one with a positive net charge.
Unlike conventional mechanical caries treatment methods the biological treatment method is usually not painful at all. Neither does it require any investments in expensive equipments. It only requires a scraping instrument to remove softened carious dentine material.
Traditional excavator instruments, however, are not suitable for this purpose as they are cutting and not made for just scraping away already softened dentine material from different types of cavities and therefore could damage healthy dentine.
An instrument specifically made for removing softened carious dentine is previously disclosed in SE 96.04626-3. This instrument makes it possible to manually scrape in different directions and the scraping edges of the tool head of the instrument are adapted to all types of caries lesions. The instrument comprises a star-shaped tool head having four symmetrically arranged scraping edges with a curved, preferably spherical, outer contour (periphery) for scraping away softened carious substance.
The instrument can also be used to pick up drops of the liquid solution used for the chemical-mechanical treatment method and apply these drops to the caries lesion. This is possible because of the open, empty spaces which are formed between the scraping edges of the tool head of the instrument and this function of the instrument is facilitated as the liquid solution which is used has a viscous, gel form.
So by using this type of scraping instrument which then also functions as a simple applicator for the gel used for the treatment, there is no need for the dentist to invest money in any expensive equipments for distribution and application of the liquid gel solution.
However, in cases where a relatively large amount of liquid is required for the treatment, it might be time-consuming to use any of said instruments as applicators as the instrument cannot pick up and carry so much volume of the liquid that would have been desired.
In SE 9700960-9 it is described a scraping instrument in which the tool head member has drop catching means in order to improve the ability to catch and carry liquid drops. The drop catching means can be made in the form of collars, flanges, surface enlargement portions, protrusions, grooves, holes, channels or the like.
Both of these instruments are made for manually scraping softened, carious dentine, ie. the scraping motion is made by hand.
As the scraping motion should be carried out in different directions and repeated until all carious dentine has been removed, it might be a hard work for the dentist from an ergonomically point of view to fulfil the caries treatment. The dentist has to position the instrument as well as control the instrument with respect to the scraping direction. At the same time the scraping motion should not affect any of the healthy teeth. It should not be allowed to apply too heavy pressure from the instrument on the tooth.
It is an object of this invention to provide a scraping instrument which facilitates for the dentist to remove carious dentine. Specifically, it is an object to unload the specific scraping motion from the dentist so that he can concentrate on positioning the instrument. This means a more efficient treatment procedure.
A further object of this invention is to speed up the scraping operation so that each caries treatment procedure is shortened.
Also a further object of the invention is to provide a scraping instrument with a more controlled scraping motion and a more steady scraping speed, which means that the scraping motion is independent of different users of the instrument, which in turn means a more predictable result from the treatment procedure.
According to the invention the scraping instrument is power-driven, i.e. the instrument is equipped with, or connected to, for instance an electric motor for driving the tool head of the instrument according to a predetermined motion pattern. For instance it could be a rotating, low-speed motion, a reciprocating motion, a pendulating, wobbling or oscillating motion.
According to a preferred embodiment the instrument has a star-shaped tool head and a shaft for connecting the instrument to a rotating machine (power tool).
Also other tool heads could be used, such as brush type tool heads. According to a further preferred embodiment a set of different instruments, i.e. instruments with different tool heads but easy connectable to the rotating machine, could be used.